1. Field of the Invention
The present invention relates to a data transmission method. More particularly, the present invention relates to a method of distributing a conference session key which is shared in order to encrypt data between a plurality of parties.
2. Description of the Related Art
As computers become ubiquitous, networks connecting the computers become more important and useful. However, recently, attacks on computers and networks have increased. Thus, network security techniques are needed.
An inter-party key sharing protocol is a protocol used for keeping data transmitted through networks secret. A standard protocol is a Diffie-Hellman type protocol, which is based on difficulty in solving an elliptic curve cryptographic discrete logarithm problem. The Diffie-Hellman type protocol is based on a public key infrastructure (PKI) encryption. However, PKI encryption has shortcomings, e.g., requiring participation of a reliable authentication center, since integrity of a public key must be guaranteed by the authentication center.
Because of the shortcomings of PKI encryption, much research has been conducted on an ID-based key sharing protocol which is not based on PKI encryption. Unfortunately, conventional ID-based key sharing protocols have problems, e.g., they are vulnerable to a disguised attack and cannot provide forward secrecy.